Re: [PATCH 6/9] OPP: Extend support for the opp-level beyond required-opps

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
	Cristian Marussi <cristian.marussi@arm.com>,
	Viresh Kumar <vireshk@kernel.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Nishanth Menon <nm@ti.com>, Stephen Boyd <sboyd@kernel.org>,
	Nikunj Kela <nkela@quicinc.com>,
	Prasad Sodagudi <psodagud@quicinc.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/9] OPP: Extend support for the opp-level beyond required-opps
Date: Tue, 3 Oct 2023 13:53:22 +0530	[thread overview]
Message-ID: <20231003082322.cmok766jxzftsgrg@vireshk-i7> (raw)
In-Reply-To: <CAPDyKFo+XCEtTSNqtA1SeajWo4tuRroA4GrRegta5TsqSGd4eQ@mail.gmail.com>

On 25-09-23, 15:33, Ulf Hansson wrote:
> On Mon, 25 Sept 2023 at 15:18, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> >
> > At this point the level (performance state) for an OPP is currently limited
> > to be requested for a device that is attached to a PM domain.  Moreover,
> > the device needs to have the so called required-opps assigned to it, which
> > are based upon OPP tables being described in DT.
> >
> > To extend the support beyond required-opps and DT, let's enable the level
> > to be set for all OPPs. More precisely, if the requested OPP has a valid
> > level let's try to request it through the device's optional PM domain, via
> > calling dev_pm_domain_set_performance_state().
> >
> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> > ---
> >  drivers/opp/core.c | 29 +++++++++++++++++++++++++++++
> >  1 file changed, 29 insertions(+)
> >
> > diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> > index 60dca60ac4af..afb73978cdcb 100644
> > --- a/drivers/opp/core.c
> > +++ b/drivers/opp/core.c
> > @@ -1107,6 +1107,22 @@ void _update_set_required_opps(struct opp_table *opp_table)
> >                 opp_table->set_required_opps = _opp_set_required_opps_generic;
> >  }
> >
> > +static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
> > +                         struct dev_pm_opp *opp)
> > +{
> > +       int ret = 0;
> > +
> > +       /* Request a new performance state through the device's PM domain. */
> > +       if (opp && opp->level) {
> > +               ret = dev_pm_domain_set_performance_state(dev, opp->level);
> > +               if (ret)
> > +                       dev_err(dev, "Failed to set performance state %u (%d)\n",
> > +                               opp->level, ret);
> > +       }
> 
> Okay, so reviewing my own code found a problem here. We need an "else"
> here, that should request the performance state to be set to 0.
> 
> I am not sending a new version at this point, but awaiting more feedback first.

I am looking to add below to this patch, is that okay with you ?

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 7b505316bb1c..a113e9caaa5a 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1135,16 +1135,22 @@ void _update_set_required_opps(struct opp_table *opp_table)
 static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
                          struct dev_pm_opp *opp)
 {
+       unsigned int level = 0;
        int ret = 0;

-       /* Request a new performance state through the device's PM domain. */
-       if (opp && opp->level) {
-               ret = dev_pm_domain_set_performance_state(dev, opp->level);
-               if (ret)
-                       dev_err(dev, "Failed to set performance state %u (%d)\n",
-                               opp->level, ret);
+       if (opp) {
+               if (!opp->level)
+                       return 0;
+
+               level = opp->level;
        }

+       /* Request a new performance state through the device's PM domain. */
+       ret = dev_pm_genpd_set_performance_state(dev, level);
+       if (ret)
+               dev_err(dev, "Failed to set performance state %u (%d)\n", level,
+                       ret);
+
        return ret;
 }

I am switching back to dev_pm_genpd_set_performance_state() as I won't be
applying the power domain changes. I will then push out a branch and you can
rebase your patches on top of it ? And then probably Sudeep or someone else can
apply everything ?

-- 
viresh
